Milling of flex foil with two conductive layers from both sides

Abstract

A method for milling flex foil includes providing a web ( 14 ) of flex foil including a substrate; a first conductive layer arranged on one surface of the substrate; a second conductive layer arranged on an opposite surface of the substrate; a first insulating layer arranged adjacent to the first conductive layer; and a second insulating layer arranged adjacent to the second conductive layer. The method includes dry milling one side of the web using a milling wheel ( 20 - 1 ) and a first cliche pattern ( 25 - 1 ) (including a rotating drum ( 24 - 1 ) and a flexible substrate ( 26 - 1 )) including raised portions and non-raised portions to selectively remove at least one of the first conductive layer and the first insulating layer. The method includes dry milling an opposite side of the web using a milling wheel ( 20 - 2 ) and a second cliche pattern ( 25 - 2 ) including upper raised portions, lower raised portions and non-raised portions to selectively remove the second insulating layer.

What is claimed is: 
     
       1. A method for milling flex foil, comprising:
 providing a web of flex foil including:
 a substrate; 
 a first conductive layer arranged on one surface of the substrate; 
 a second conductive layer arranged on an opposite surface of the substrate; 
 a first insulating layer arranged adjacent to the first conductive layer; and 
 a second insulating layer arranged adjacent to the second conductive layer; 
 
 dry milling one side of the web using a first cliché pattern including raised portions and non-raised portions to selectively remove only the first conductive layer and the first insulating layer; and 
 dry milling an opposite side of the web using a second cliché pattern including upper raised portions, lower raised portions and non-raised portions to selectively remove only the second insulating layer. 
 
     
     
       2. The method of  claim 1 , wherein the first cliché pattern removes the at least one of the first insulating layer and the first conductive layer adjacent to the raised portions and does not remove the first insulating layer and the first conductive layer adjacent to the non-raised portions. 
     
     
       3. The method of  claim 1 , wherein the upper raised portions of the second cliché pattern remove the second insulating layer on the opposite side of the web at locations where the at least one of the first insulating layer and the first conductive layer are removed. 
     
     
       4. The method of  claim 3 , wherein the lower raised portions of the second cliché pattern remove the second insulating layer on the opposite side of the web at locations where the at least one of the first insulating layer and the first conductive layer are not removed. 
     
     
       5. The method of  claim 4 , wherein the non-raised portions of the second cliché pattern do not remove the second insulating layer. 
     
     
       6. The method of  claim 1 , further comprising:
 feeding the web between a first milling wheel, arranged on the one side of the web, and a first cliché arranged on the opposite side of the web, wherein the first cliché includes the first cliché pattern; and 
 feeding the web between a second milling wheel, arranged on the opposite side of the web, and a second cliché located on the one side of the web, wherein the second cliché includes the second cliché pattern. 
 
     
     
       7. The method of  claim 1 , further comprising:
 feeding the web between a first milling wheel, arranged on the one side of the web, and a first cliché arranged on the opposite side of the web, wherein the first cliché includes the first cliché pattern; 
 changing the first cliché pattern on the first cliché to the second cliché pattern; 
 inverting and aligning the web; and 
 feeding the web between the first milling wheel and the first cliché. 
 
     
     
       8. The method of  claim 1 , wherein the first conductive layer and the second conductive layer have a thickness in a range from 5 μm to 40 μm.